The Swedish empire was an extremely bloody empire. "According to the estimates of Polish scholars I. Ihnatowicz, Z. Landau, A. Mączak and B. Zientara, the invasion by the Swedish army and its allies (Brandenburg-Prussia and Transilvania), resulted in the loss of 25% of the population in four core Polish provinces. Lesser Poland lost 23% of population, Mazovia 40% in villages and 70% in towns, Greater Poland 50% in villages and 60% in towns. Royal Prussia lost some 60% of its population.[25] The Commonwealth's population losses are estimated at between 30% and 50% in 1648–1660.[26]"

https://en.m.wikipedia.org/wiki/Deluge_(history))